Download Agreement of Cerebral State Index and Glasgow Coma Scale in

Arch Trauma Res. 2014 March; 3(1): e15892.
DOI: 10.5812/atr.15892
Research Article
Published online 2014 March 30.
Agreement of Cerebral State Index and Glasgow Coma Scale in Brain-Injured
Patients
1
1,*
1
1
Mehrdad Mahdian ; Mohammad Reza Fazel ; Esmaeil Fakharian ; Hossein Akbari ; Soroush
2
3
Mahdian ; Soheila Yadollahi
1Trauma Research Center, Kashan University of Medical Sciences, Kashan, IR Iran
2Student Research Committee, Arak University of Medical Sciences, Arak, IR Iran
3Shahid-Beheshti Hospital, Kashan University of Medical Sciences, Kashan, IR Iran
*Corresponding author: Mohammad Reza Fazel, Trauma Research Center, Kashan University of Medical Sciences, Kashan, IR Iran. Tel: +98-9132760380, Fax: +98-3615558883,
E-mail: [email protected]
Received: November 1, 2013; Revised: December 17, 2013; Accepted: December 21, 2013
Background: Variables derived from electroencephalogram like cerebral state index (CSI) have been used to monitor the anesthesia
depth during general anesthesia. Observed evidences show such variables have also been used as a detector of brain death or outcome
predictor in traumatic brain-injured (TBI) patients.
Objectives: The current study was designed to determine the correlation between Glasgow coma score (GCS) and CSI among TBI patients.
Patients and Methods: In 60 brain-injured patients who did not need and receive sedatives, GCS and CSI were daily measured during
the first ten days of their hospital stay. Correlation between GCS and CSI was studied using the Pearson’s correlation test. The Gamma
agreement coefficient was also calculated between the two variables for the first day of hospitalization.
Results: A significant correlation coefficient of 0.611-0.796 was observed between CSI and GCS in a ten-day period of the study (P < 0.001).
Gamma agreement coefficient was 0.79 (P < 0.001) for CSI and GCS for the first day of hospitalization. An increased daily correlation was
observed in both CSI and GCS values. However, this increase was less significant in CSI compared with the GCS.
Conclusions: A statistically significant correlation and agreement was found between GCS and CSI in the brain-injured patients and GCS
was also found to be more consistent and reliable compared with CSI.
Keywords:Cerebrum; Glasgow Coma Scale; Brain Injury
1. Background
Traumatic brain injury (TBI) is one of the major causes
of post-injuries mortality and disability, worldwide (1).
TBI is characterized by the loss of consciousness and
Glasgow coma scale (GCS) is used for routine assessment
of the patients' consciousness level. In non-traumatic unconsciousness like during anesthesia, variables derived
from electroencephalogram (EEG) like bispectral index
(BIS) and cerebral state index (CSI) have been widely
used to monitor the depth of anesthesia objectively and
quantitatively (2). Among these indices further studies
have been undertaken based on BIS (3-5). Many investigators have tried to broaden the monitoring use of BIS for
TBI patients (6, 7) and among those many studies found
a significant correlation between BIS and GCS (8-11) and
some did not (12). The CSI value which was introduced as
a new instrument for measuring hypnotic depth in 2004,
is passively derived from EEG and demonstrates a dimensionless score from 0 to 100 (13-16). Unlike BIS, few studies
have been performed on CSI monitoring in brain-injured
patients. This study was conducted to determine the cor-
relation and agreement between GCS and CSI in unsedated traumatic brain- injured patients.
2. Objectives
The purpose of this study was to assess the degree of
agreement and correlation between GCS as a subjective
and CSI as an objective method to evaluate the consciousness in TBI patients.
3. Patients and Methods
This prospective observational study was performed
after approval and informed consent in patients with
mild (GCS 13-15), moderate (GCS 9-12) and severe (GCS
3-8) head injury. All patients had been admitted to the
neurosurgical ICU of Shahid-Beheshti Hospital, Kashan
University of Medical Sciences, Iran, between December 2011 and March 2012. Demographic characteristics,
mechanism of head injury, GCS, computed tomography
scan, and neurological examination at the time of admission were recorded. Patients demanding sedatives were
excluded from the study. Since some of the patients un-
Implication for health policy/practice/research/medical education:
The results of this study can be used by researchers in fields of nursing, neurosurgery, neuroscience and practitioners as well.
Copyright © 2014, Kashan University of Medical Sciences; Published by Kowsar Corp. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Mahdian M et al.
derwent intracranial surgical operation, to eliminate
the effect of anesthesia on consciousness indices, GCS
and CSI were measured three hours after recovery from
general anesthesia in these cases. Respiratory and metabolic disorders were considered as exclusion criteria, due
to their potential effects on GCS, and patients with such
problems did not enter the study. CSI was measured after the ICU admission and afterwards on a daily basis for
the next nine days. CSI was measured using CSI monitor
(CSI™Danmeter, Odese, Denmark). To measure CSI, the patient's skin was prepared by swapping with alcohol and
wiping. Standard electrocardiogram electrodes (SKINTACT®, Leonard Long GmbH, Innsbruk, Austria) were
then positioned as recommended by the manufacturer.
After controlling of electrode impedance, the numerical
value of CSI, ranging 0-100, was recorded for each patient
by a nurse who was blinded to the study. Patients' neurological status was assessed using the GCS and recorded, at
the moment of CSI measuring.
3.1. Statistical Analysis
Correlation between GCS and CSI was calculated using
Pearson's correlation test. To eliminate the effect of surgical operation and patients' death on the study, adjustments regarding these factors were performed and partial correlation was calculated in addition to the crude
correlation. Gamma agreement coefficient was also calculated between two variables for the first day of hospi-
talization. Mean and standard deviations for CSI and GCS
values in brain injured patients in different days were
also compared using t-test.
4. Results
A total of 60 brain-injured patients (53 male and seven
female cases) aged (mean ± SD) 33.4 ± 17.1 years were included in the study. The injury mechanism was road traffic
accident in 49 cases, falling in nine and assault in two patients. Fourteen patients had mild injury, 13 had moderate
and 33 had severe injuries. The majority of cases were admitted to the ICU due to subdural hematoma and during
the course of the study 26 cases underwent surgical operation due to intracranial mass lesion and 17 patients (28.3%)
expired due to their condition deterioration (Table 1). Ten
sets of data were collected for each patient. An increased
daily correlation was observed in both CSI and GCS values.
However, this increase was less significant for CSI than that
of the GCS. A significant correlation coefficient (crude correlation) of 0.611-0.796 between CSI and GCS was observed
in the ten-day study. A significant partial correlation was
also noted between the two indices regarding adjustment
of surgical operation and death during the study period
(Table 2). The highest correlation coefficient between GCS
and CSI in all the patients was observed on the sixth day
of hospitalization (r = 0.796, P < 0.001) (Figure 1). Gamma
agreement coefficient for CSI and GCS was 0.79 (P < 0.001)
for the first day of hospitalization.
Table 1. Patients' Outcomes Regarding Their CT Scan-Based Diagnoses a
Outcome Diagnosis
Subdural hematoma
Epidural hematoma
Cerebral contusion
Death
Transfer to Post-ICU Ward
Sum
8 (42.1)
11 (57.9)
19
2 (11.8)
15 (88.2)
4 (40)
6 (60)
10
43 (71.7)
60
2 (22.2)
Diffuse axonal injury
Intracranial Hemorrhage
1 (20)
Sum
17 (28.3)
a All data are expressed as No (%).
17
7 (77.8)
9
4 (80)
5
Table 2. Correlation Between GCS and CSI in Different Days of Hospitalization (Including Crude and Adjusted Correlation Regarding
Death and Surgical Operation)
Correlation, Days
1
2
3
4
5
6
7
8
9
10
2
Crude Correlation
Partial Correlation Adjusted
for Death
Partial Correlation Adjusted for Surgical
Operation
0.648
0.473
0.479
0.723
0.787
0.619
0.695
0.661
0.723
0.739
0.726
0.796
0.725
0.628
0.721
0.68
0.612
0.731
0.772
0.79
0.73
0.662
0.529
0.646
0.682
0.504
0.68
0.611
0.457
0.6
Arch Trauma Res. 2014;3(1):e15892
Mahdian M et al.
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
1
2
3
4
5
6
7
8
9
10
Days
Figure 1. Correlation Coefficient and 95% Confidence Interval of GCS and
CSI During Hospitalization
5. Discussion
The present study showed that there is a statistically
significant correlation and agreement between GCS and
CSI in patients with traumatic brain injury. Although we
have found a correlation between GCS and CSI in patients
during all days of hospitalization, interestingly, we found
GCS was more consistent than the CSI.
Basically, cerebral state index has been developed for
monitoring the depth of anesthesia during operations.
Its predecessor, BIS, has been also used for monitoring
of consciousness during the management of both traumatic and non-traumatic coma (6, 17). The CSI, like BIS, is
a quantitative EEG derived measure index that provides a
dimensionless score from 0 to 100 to characterize the level of hypnosis. Although EEG monitoring is the gold standard for intraoperative monitoring of cerebral ischemia
but common monitoring of EEG is inconvenient and obtaining signals without artifacts may be difficult in the
operating room and intensive care settings (6). Therefore, it is preferable to use simple tools to measure BIS or
CSI. Unlike BIS that was used in many studies to evaluate
the consciousness state and diagnosis of brain death in
comatose patients (6, 7, 11, 18-21), limited clinical studies
have been conducted on the CSI in this area. Of course
there are series of studies showing values of CSI and BIS,
which are not significantly different (22-24). However,
as previously mentioned, BIS measurement has recently
been used for patients with traumatic brain injuries with
severity of the injury (6, 7, 10, 20). The findings of the present study are consistent with previous observations and
suggested that CSI values also correlate with severity of
brain injury. These findings also corroborate the ideas of
Ming XU et al. (2011), suggested that CSI monitoring presumably is a reliable objective technique to predict consciousness level of patients following elective intracranial surgeries (25). However, the findings of the current
study does not support the published study by Nasraway
et al. (2002) (12) who compared BIS with the sedationArch Trauma Res. 2014;3(1):e15892
agitation scale (SAS) as a subjective tool for monitoring
of consciousness in critically ill patients. They concluded
that the correlation between SAS and BIS scores was less
than optimum and unpredictable in a different group of
ICU patients. This inconsistency with our results may be
due to the nature of the two subjective tools. They used
SAS while the index used in the present study was GCS. In
addition, this study was performed on the brain-injured
patients while they studied on a heterogeneous group of
patients. Finally, a significant correlation and agreement
was found between GCS and CSI in brain-injured patients.
So, CSI can be used as an adjunct to GCS to evaluate the
consciousness in these patients.
Acknowledgements
The authors gratefully would like to thank Kashan University of Medical Sciences for the support. The authors
also would like to thank Mr. Amir Motamed Nejad, Ms.
Fatemeh Gholami and the staff of the intensive care unit
of Kashan Shahid-Beheshti Hospital for their assistance
in data gathering.
Authors’ Contribution
Mehrdad Mahdian was in charge of idea, design and
implementation of the study, Mohammad Reza Fazel supervised it, Esmaeil Fakharian took responsibility of the
result interpretation, Hossein Akbari did the statistical
analysis, Soroush Mahdian revised the study draft and Soheila Yadollahi was in charge of the data collection.
Financial Disclosure
The authors declare that there is no conflict of interest.
Funding/Support
This study was supported by Deputy of Research, Kashan
University of Medical Sciences (Grant no: 8914).
References
1.
2.
3.
4.
5.
6.
Utomo WK, Gabbe BJ, Simpson PM, Cameron PA. Predictors of
in-hospital mortality and 6-month functional outcomes in older
adults after moderate to severe traumatic brain injury. Injury.
2009;40(9):973–7.
Wang Q, Xu M, Lei YN, Wang GN, Zhou JX. Use of cerebral state
index monitoring to detect purposeful movement in unsedated
brain-injured patients. J Int Med Res. 2009;37(3):689–96.
Bresil P, Nielsson MS, Malver LP, Kraemer K, Schjorring O, Dethlefsen C, et al. Impact of bispectral index for monitoring propofol
remifentanil anaesthesia. A randomised clinical trial. Acta Anaesthesiol Scand. 2013;57(8):978–87.
Krieger A, Panoskaltsis N, Mantalaris A, Georgiadis M, Pistikopoulos E. Modelling and analysis of individualized pharmacokinetics and pharmacodynamics for volatile anaesthesia. IEEE Trans
Biomed Eng. 2013.
Cheung YM, Scoones GP, Hoeks SE, Stolker RJ, Weber F. Evaluation
of the aepEX monitor of hypnotic depth in pediatric patients
receiving propofol-remifentanil anesthesia. Paediatr Anaesth.
2013;23(10):891–7.
Paul DB, Umamaheswara Rao GS. Correlation of Bispectral Index
with Glasgow Coma Score in mild and moderate head injuries. J
3
Mahdian M et al.
7.
8.
9.
10.
11.
12.
13.
14.
15.
4
Clin Monit Comput. 2006;20(6):399–404.
Fabregas N, Gambus PL, Valero R, Carrero EJ, Salvador L, Zavala E,
et al. Can bispectral index monitoring predict recovery of consciousness in patients with severe brain injury? Anesthesiology.
2004;101(1):43–51.
Simmons LE, Riker RR, Prato BS, Fraser GL. Assessing sedation
during intensive care unit mechanical ventilation with the
Bispectral Index and the Sedation-Agitation Scale. Crit Care Med.
1999;27(8):1499–504.
Riker RR, Fraser GL, Simmons LE, Wilkins ML. Validating the Sedation-Agitation Scale with the Bispectral Index and Visual Analog
Scale in adult ICU patients after cardiac surgery. Intensive Care
Med. 2001;27(5):853–8.
Deogaonkar A, Gupta R, DeGeorgia M, Sabharwal V, Gopakumaran B, Schubert A, et al. Bispectral Index monitoring correlates
with sedation scales in brain-injured patients. Crit Care Med.
2004;32(12):2403–6.
Gilbert TT, Wagner MR, Halukurike V, Paz HL, Garland A. Use of
bispectral electroencephalogram monitoring to assess neurologic status in unsedated, critically ill patients. Crit Care Med.
2001;29(10):1996–2000.
Nasraway SS, Jr., Wu EC, Kelleher RM, Yasuda CM, Donnelly AM.
How reliable is the Bispectral Index in critically ill patients? A
prospective, comparative, single-blinded observer study. Crit
Care Med. 2002;30(7):1483–7.
Anderson RE, Barr G, Jakobsson JG. Cerebral state index during
anaesthetic induction: a comparative study with propofol or nitrous oxide. Acta Anaesthesiol Scand. 2005;49(6):750–3.
Hoymork SC, Hval K, Jensen EW, Raeder J. Can the cerebral state
monitor replace the bispectral index in monitoring hypnotic
effect during propofol/remifentanil anaesthesia? Acta Anaesthesiol Scand. 2007;51(2):210–6.
Anderson RE, Sartipy U, Jakobsson JG. Use of conventional ECG
electrodes for depth of anaesthesia monitoring using the ce-
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
rebral state index: a clinical study in day surgery. Br J Anaesth.
2007;98(5):645–8.
Anderson RE, Jakobsson JG. Cerebral state index: comparison between pairwise registrations from the left and the right sides of
the brain. Br J Anaesth. 2006;97(3):347–50.
Fraser GL, Riker RR. Bispectral index monitoring in the intensive
care unit provides more signal than noise. Pharmacotherapy.
2005;25(5 Pt 2):19S–27S.
Dunham CM, Katradis DA, Williams MD. The bispectral index, a
useful adjunct for the timely diagnosis of brain death in the comatose trauma patient. Am J Surg. 2009;198(6):846–51.
Schnakers C, Ledoux D, Majerus S, Damas P, Damas F, Lambermont B, et al. Diagnostic and prognostic use of bispectral index in coma, vegetative state and related disorders. Brain Inj.
2008;22(12):926–31.
Ebtehaj M, Yaqubi S, Seddighi AS, Seddighi A, Yazdi Z. Correlation
between BIS and GCS in patients suffering from head injury. Ir J
Med Sci. 2012;181(1):77–80.
Vivien B, Paqueron X, Le Cosquer P, Langeron O, Coriat P, Riou B.
Detection of brain death onset using the bispectral index in severely comatose patients. Intensive Care Med. 2002;28(4):419–25.
Cortinez LI, Delfino AE, Fuentes R, Munoz HR. Performance of
the cerebral state index during increasing levels of propofol anesthesia: a comparison with the bispectral index. Anesth Analg.
2007;104(3):605–10.
Nishiyama T, Komatsu K. Cerebral state index versus bispectral
index during propofol-fentanyl-nitrous oxide anesthesia. J Anesth. 2010;24(3):380–5.
Nishiyama T. Cerebral state index vs. bispectral index during sevoflurane-nitrous oxide anaesthesia. Eur J Anaesthesiol.
2009;26(8):638–42.
Xu M, Lei YN, Zhou JX. Use of cerebral state index to predict longterm unconsciousness in patients after elective craniotomy with
delay recovery. BMC Neurol. 2011;11:15.
Arch Trauma Res. 2014;3(1):e15892